1. Field of the Invention
The invention relates to new 2-substituted alkyl-3-carboxy carbapenems having the formula: ##STR3## with R.sup.1, R.sup.2, R.sup.3, X and Y defined hereafter as antibiotics and beta lactamase inhibitors produced novel Michael addition-elimination reaction of a substituted situated allyl azetidinone in the reaction shown: ##STR4## with R.sup.1, R.sup.2, Q, X and Y defined hereafter